Leaked' U.N. Climate Change Report Says Global Warming Claims 'Exaggerated' -- but Scientists Are Fighting Back

A U.K. tabloid newspaper claimed to have a leaked, final copy of the a U.N. climate change report, saying it revealed the panel was rolling back "exaggerated" claims of global warming. But a scientist is not only refuting the claims but also the alleged "leak" of the report as well.

"...a leak is actually not the most appropriate term here, because just about anyone could sign up and receive the early draft" of the report, John Cook, with the Global Change Institute at the University of Queensland, told Radio Australia.

"So these leaks aren't done necessarily by the climate fighters who are writing the reports. They're most likely done just by anyone online, on the internet, who signed up to be a commentator. So it's not like a whistleblower, finding something sensational," Cook, the creator of skepticalscience.com, continued.

The International Panel of Climate Change is set to publish its final assessment report next week but the Sunday Mail Online claimed to have obtained a copy that reportedly scales back earlier predictions.

The Daily Mail wrote:

The IPCC is set to release its fifth assessment report this month. It released its fourth report in 2007. (Image: IPCC)

Yet the leaked report makes the extraordinary concession that the world has been warming at only just over half the rate claimed by the IPCC in its last assessment,  published in 2007. 

Back then, it said that the planet was warming at a rate of 0.2C every decade – a figure it claimed was in line with the forecasts made by computer climate models.

But the new report says the true figure since 1951 has been only 0.12C per decade – a rate far below even the lowest computer prediction.

[...]

It also surprisingly reveals: IPCC scientists accept their forecast computers may have exaggerated the effect of increased carbon emissions on world temperatures  – and not taken enough notice of natural variability.

They (recognize) the global warming ‘pause’ first reported by The Mail on Sunday last year is real – and concede that their computer models did not predict it. But they cannot explain why world average temperatures have not shown any statistically significant increase since 1997.

Georgia Tech professor Judith Curry, who has been labeled as a "climate misinformer" by skepticalscience.com, told the Mail Online the report summary shows "the science is clearly not settled, and is in a state of flux."

Matt Ridley, author of "The Rational Optimist" and a member of the British House of Lords, also claimed to have received a copy of the final report. In an article published by the Wall Street Journal, Ridley wrote that lower greenhouse gas emissions than previously predicted in the 2007 report is "significant because it points to the very real possibility that, over the next several generations, the overall effect of climate change will be positive for humankind and the planet."

Here's how, according to Ridely:

Warming of up to 1.2 degrees Celsius over the next 70 years (0.8 degrees have already occurred), most of which is predicted to happen in cold areas in winter and at night, would extend the range of farming further north, improve crop yields, slightly increase rainfall (especially in arid areas), enhance forest growth and cut winter deaths (which far exceed summer deaths in most places). Increased carbon dioxide levels also have caused and will continue to cause an increase in the growth rates of crops and the greening of the Earth—because plants grow faster and need less water when carbon dioxide concentrations are higher.

Up to two degrees of warming, these benefits will generally outweigh the harmful effects, such as more extreme weather or rising sea levels, which even the IPCC concedes will be only about 1 to 3 feet during this period.

In response to the conclusions some are forming from the "leak," Cook told Radio Australia the estimate isn't being scaled back from the prior report.

"Now in 2007, the IPCC said that their best estimates, climate sensitivity was three degrees, so if we doubled carbon dioxide in the atmosphere, then we should experience three degrees of global warming," Cook said. "Now, in the latest IPCC report, which is due in about a week or so, the best estimate, the climate sensitivity is still three degrees Celsius, so that hasn't changed at all.

"What has changed is the range of very likely value, so they give a best estimate, but then they also give a range of possible values."

Although he says the IPCC could work on making its report more understandable, he said the science is "complicated" and that he doesn't think the panel is to blame for "public confusion."

"I think the main culprit is articles in conservative newspapers which really only give you pieces of the puzzle and don't give you the overall picture and an accurate picture of what the science is telling us," Cook said.

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